1. Field of the Invention
The present invention relates to a construction equipment cab having a protective structure capable of ensuring the safety of an operator from cab deformation in the event of a rollover accident
More particularly, the present invention is concerned with a construction equipment cab having a protective structure (e.g., Roll Over Protective Structure; ROPS) mounted at the rear of the cab to protect an operator from injury due to deformation of the cab in the event of a rollover accident, the cab being capable of preventing the protective structure from protruding outwardly from the rear of the cab, simplifying a structure of the protective structure, and effectively dispersing a load transmitted to the construction equipment cab in a rollover accident.
2. Description of the Related Art
In case a frame-shaped protective structure is directly mounted in the front of a cabin (simply called a cab) of construction equipment such as bulldozers, snowplows, backhoes, etc., the cab is generally vulnerable to a load applied to the sides or rear thereof. For example, when there is a rollover accident on a slope, or when sudden load is applied to a cab by a heavy object, the cab is damaged or is excessively deformed, which may result in injury to a driver or operator.
For that reason, several protective structures have been prescribed. A Roll Over Protective Structure (ROPS) is intended to prevent a cab of construction equipment, which is deformed when the construction equipment rolls over, from coming into contact with the body of an operator. A Falling Object Protective Structure (FOPS) is intended to prevent both a cab of construction equipment that is deformed when a heavy object falls onto the cab during work, and the heavy object itself, from coming into contact with the body of an operator. A Tip Over Protective Structure (TOPS) is intended to prevent both a cab of construction equipment that is deformed when a heavy object collides with the side or rear of the cab during work, and the heavy object itself, from coming into contact with the body of an operator.
These protective structures for the cab are designed to reinforce the strength of the front, rear or top of the cab such that the cab does not deform so much as to invade the space of the operator in an accident.
In a conventional construction equipment cab having a protective structure as shown in FIGS. 1 and 2, the cab 2 is mounted on an upper swivel body I (on top of a lower travelling body (not shown)), and the protective structure 3 is fixed to the upper swivel body 1 and an outer face of the cab 2 such that a driver or operator can be protected from injury due to deformation of the cab 2 when the construction equipment rolls over.
The protective structure 3 is fixed to the upper swivel body 1 at a lower end thereof by bolts 4. Fastening members 5 fixed to an upper end of the protective structure 3 are coupled to coupling holes of hooks 6, which are formed on a rear outer face of the cab 2 to be opposite to each other, and then are fastened by fastening plates 7 screwed thereto.
This protective structure 3 is composed of vertical members 3a and horizontal members 3b, and protrudes backward from the cab 2, so that it is impossible to secure sufficient space to mount a radiator 8, a battery, etc. in the rear of the cab 2. (Particularly, in the case of zero tail type construction equipment in which a door 2a of the cab 2 can swing open and closed, there is insufficient space in the rear of the cab 2.)
Further, when the cab 2 is assembled on an assembly line, the fastening members 5 fixed to the upper end of the protective structure 3 are inserted into the coupling holes (formed in a vertical direction) of the horizontal hooks 6. Then, the lower end of the protective structure 3 is fixed to the upper swivel body 1 by the bolts 4, and the upper end of the protective structure 3 is fastened to the hooks 6 by the fastening plates 7. As a result, more time is required to assemble the cab 2 so that work efficiency falls.
Further, the members that fix the protective structure 3 to the cab 2 have a complicated structure, which increases the number of parts so that production cost increases.
Furthermore, in the case in which the weight of the construction equipment is transmitted to the side, etc. of the cab 2 due to a rollover accident during work, a load is transmitted to the fastening members 5 via the protective structure 3. Thus, the load is not effectively dispersed, the protective structure 3 is deformed or damaged, and impact is directly transmitted to the operator, which amounts to reduced safety and reliability.